The present invention relates to a storage device and an information appliance connected to the storage device. In particular, it relates to a method of controlling the data transfer between the information appliance and the storage device.
In recent years, the development of the network society based on the Internet and so on has been increasing the importance of a technology for protecting the copyright of the content such as music and an image circulated on the network. As the copyright-protecting technology, there has been proposed a memory IC card. The memory IC card mounts thereon a private-key storing circuit for storing a private key used for the encryption/decryption and a data storing circuit for saving the data, and also has a function of using a writing-in controlling circuit so as to write the private key into the private-key storing circuit and a function of authenticating the opposite appliance. This technology has been disclosed in, e.g., JP-A-2000-163547.
In JP-A-2000-163547, all the data are recorded in a storage medium on a packaged storage device such as the memory IC card. In order to prevent the stealing of the content or the like, the packaged storage device such as the memory IC card has a structure (i.e., a tamper-resistant module) that is configured so that analyzing the inside data from the outside is difficult. Generally speaking, however, the packaged storage device such as the memory IC card having the tamper-resistant module is expensive, and its memory's storage-capacity is small. Consequently, it was very difficult to store high-security data in large quantities into the packaged storage device such as the memory IC card.
Also, in JP-A-2000-163547, the packaged storage device such as the memory IC card has stored the high-security data and low-security data together into the tamper-resistant module. Namely, the device has done this without making a judgement on the differentiation of the high-security data and the low-security data just in response to a transfer instruction from a higher-order device. This has resulted in a state where data that need not be secured have also been all stored into the tamper-resistant module, thereby making it impossible to effectively utilize the storage area within the tamper-resistant module.
Also, in JP-A-2000-163547, a non-volatile memory (hereinafter, referred to as “an NV memory”) such as an EEPROM has been used as the data-saving storage area. Concerning the NV memory used in the prior art, however, its rewritable number is small and accordingly it was difficult to replace the content many times.
Moreover, in JP-A-2000-163547, the packaged storage device such as the memory IC card, as described above, is small in its storage-capacity. This condition, even when applications are executed on the memory IC card, has allowed only the execution of an application whose program uses just a small storage-capacity.
Meanwhile, in JP-A-10-334205, there has been disclosed a card where an IC chip and a flash memory are built-in. However, since the IC chip and the flash memory are independent of each other, it is impossible for the IC chip to write or read the data into or from the flash memory.